Well packer assemblies



Feb. 25, 1964 c. c. BROWN ETAL 3,122,205

WELL PACKER ASSEMBLIES Filed Nov. 14, 1960 s Sheets-Sheet 1 C/CERO 0. BROWN CHUDl/EGH 5 000/154 1 N V EN TORS WMWJA; 5 820% ATTORNEYS Feb. 25, 1964 c. c. BROWN ETAL 3,122,205

WELL PACKER ASSEIBLIES Filed NOV. 14, 1960 3 Sheets-Sheet 2 C/CERO CBPOWN CHUDL/EG'H B.COC'HRAN INVENTOR.

ATTORNEYS Feb. 25, 1964 c. c. BROWN ETAL 3,122,205

WELL PACKER ASSEMBLIES Filed Nov. 14, 1960 3 Sheets-Sheet 3 C/CERO C. BROWN CH UDL IEGH B COCA/RAN I N V EN TOR.

BY 5510M A TTORNE Y5 United States Patent 3,122,265 WELL PACKER ASSEMBLIES Cicero C. Brown and Chudleigh E. Cochran, Houston,

Tex., assignors, by direct and mesne assignments, to

Brown Gil Toels, Inc., Houston, Tex., a corporation of Texas Filed Nov. 14, 1960, Ser. No. 69,168 9 Claims. (Cl. 166-122) This invention relates to new and useful improvements in well packer assemblies.

Well packer assemblies capable of holding differential pressures from either above or below require the use of two anchoring units, one for maintaining the assembly against upward displacement and the other for preventing downward displacement. The setting of the anchoring units presents no particular problem and several types are in general use wherein the anchoring units, as well as the packing element of the assembly are moved into set and sealing position hydraulically by the application of pressure fluid. However, where two anchoring units which look the assembly against movement in either direction are used, the release of the units to permit removal of the assembly presents a considerable problem.

Various attempts have been made to provide releasable means for this type of well packer assembly and one example is illustrated in my co-pending application Serial No. 784,503 filed January 2, 1959, now abandoned. In such application, release of the assembly from its set position is effected by imparting a rotation to the tubing string on which the assembly is mounted. This is a satisfactory structure and accomplishes the purposes, provided that the packer assembly is not at too deep an elevation within the well. the well bore that the assembly is located the more diflicult it becomes to manipulate or rotate the tubing string in order to release the assembly. Furthermore, since release is dependent upon tubing rotation operating a threaded connection, rust and corrosion may jam the same to make release difiicult; also, the well head equipment must be disturbed before such rotation can be imparted to said tubing and under some circumstances, it may not be desirable to uncouple said well head equipment prior to unsetting of the well packer assembly.

It is, therefore, one object of this invention to provide a well packer assembly having means for locking same against movement in either direction within the well bore, together with hydraulically-actuated means, for releasing said locking means to permit removal of the complete assembly from the well bore.

Another object is to provide a well packer assembly having upper and lower gripping units for locking the assembly against movement in either direction within a well bore, wherein said gripping elements are moved into set or gripping position by a hydraulically actuated means and are retracted into released or non-gripping position by additional hydraulically operatedmeans, whereby release of said gripping units is effected with out any movement or rotation of the tubing string on which the amembly is mounted, without disturbing the control head equipment at the well surface.

An important object of the invention is to provide a well packer assembly, of the character described, wherein the anchoring units are moved into a set or gripping position by the application of a suitable pressure and are constructed to remain in set position even though the pressure, which initially moved said elements to such set position is relieved; the assembly also including normally inactive means which is adapted, by the application of pressure in the tubing string upon which the packer is mounted, to apply pressure to said anchoring However, the deeper within 0 units in a direction etfecting release thereof from a gripping position.

A particular object is to provide a packer assembly of the character described in which the packer can be both set and released hydraulically without moving the tubing string which is suspended from the usual tubing head.

Still another object is to provide a packer assembly in which the support is constructed of telescoping sections, one of which carries one of the anchoring units and its packing element and the other of which carries the second anchoring unit and its packing element, together with hydraulically-actuated means for controlling the movement of the sections relative to each other to thereby control the release of said assembly.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and where in:

FIGURE 1 is a view partly in section and partly in elevation of a well packer assembly, constructed in accordance with the invention, and illustrating the various parts in the positions they assume during lowering of the assembly into the well bore;

FIGURE 2 is a similar view showing the packer in the fully set and anchored position in the well bore;

FIGURE 3 is a similar view illustrating the packer in a partially unset position with the sealing elements retracted;

FIGURE 4 is a similar view showing the packer in fully retracted position;

FIGURE 5 is a horizontal cross-sectional view taken on line 5-5 of FIGURE 3;

FIGURE 6 is a horizontal cross-sectional view taken on the line 6-6 of FIGURE 1;

FIGURE 7 is a horizontal cross-sectional view taken on line 77 of FIGURE 1; and

FIGURE 8 is a schematic view showing the packer in a released position suspended from the well head by the tubing string.

In the drawings the letter T designates the usual well tubing which extends downwardly through a well casing 10 within a well bore W. The improved well tool assembly which is herein shown and described as a well packer assembly is generally indicated by the letter P (FIG. 8) and is connected at the desired point in the tubing string. The tubing string T is suspended from the usual tubing head 11, which forms part of the surface control equipment E and the usual flow control valve 12 is disposed in the upper end of the tubing string to control flow therethrough.

The packer assembly P is adapted to be lowered into proper position within the well casing 10 by means of the tubing string T and during such lowering the packer is in an unset position. After reaching the desired elevation within the casing, the control head equipment E is properly mounted to close in the upper end of said casing and at this time the well is under control. Thereafter, the packer assembly P may be moved into set or sealing position by the application of a hydraulic pressure through the bore of the tubing string T. After the packer assembly is set, flow of well fluids from the producing formation below said assembly is upwardly through the tubing T. When it is desired to remove the packer assembly P and well tubing T, the packer assembly is moved into a released position by the application of a fluid pressure through the bore of the tubing T. The

packer assembly is one which can be set by hydraulic pressure and can be released by hydraulic pressure, whereby no movement or manipulation of the tubing string T is required at any time. This provides the very decided advantage of permitting the control head equipment E to remain in place at all times so that the well is completely under control both during setting or releasing of the assembly.

The particular construction of the packer assembly is illustrated in FIGURES 1 through 7. Referring to FIG- URE 1, which illustrates the packer assembly in an unset position, said assembly includes a main tubular support consisting of an inner tubular mandrel A and an outer tubular mandrel B. The inner mandrel A is formed of an upper tubular section 13, an intermediate tubular section 14 and a lower tubular section 15, which sections are suitably threaded together; said inner mandrel extends substantially throughout the length of the assembly. A coupling 15 is threaded onto the lower end of the mandrel and is connected through the usual collar 17 with that portion of the tubing string T below the assembly.

The outer mandrel B surrounds the inner mandrel A and has a telescoping connection therewith. Said outer mandrel comprises a lower sleeve portion 13, and an upper cylinder portion 19 with the upper end of the cylinder connected with an annular head member 21 the latter also being coupled to that portion of the tubing string which is above the assembly. A seal ring 21 seals the space between the head member 28 and the upper tubular section 13 of the inner mandrel A, while a sealing ring 22 seals the space between the lower sleeve portion 18 of the outer mandrel B and the intermediate tubular section 14 of the inner mandrel A. The bore 19a of the upper cylinder portion 19 of the outer mandrel has a piston 23 movable therein and this piston 23 is preferably formed integral with the upper tubular section 13 of the inner mandrel. Fluid which is preferably a liquid may be introduced into the cylinder 19 through a suitable back check valve 24; with the parts in the position of FIGURE 1 and liquid filling the cylinder below the piston, said liquid will lock the inner mandrel A against movement with respect to the outer mandrel B.

For selectively allowing the escape of the liquid from the bore of the cylinder 19, the inner mandrel A is formed with an escape port 25 which is located just below the piston 23. This port is normally closed by a valve sleeve 26 which is mounted Within the bore of the inner mandrel A to overlie and close said port 25; the valve sleeve 26 is maintained in port-closing position by suitable shear pins 27 (FIGURE which provide a releasable retaining means. When the shear pins 27 are fractured, the valve sleeve 26 may move downwardly to align a port 28 in said sleeve with the escape port 25, whereby liquid from within the cylinder 19 may escape into the bore of the inner mandrel. Shearing of the pins 27 is efiected by dropping a ball or closure 25? (FIGURE 3) which seats upon the sleeve, after which the application of pressure will effect downward movement of the sleeve until it seats against a stop shoulder 39. To assure positive relative movement between the inner mandrel A and the outer mandrel B when liquid is released from the cylinder 19, pressure fluid from the tubing string is directed into the area above the piston 23 through an opening 31 provided in the wall of the upper section 13 of the inner 'mandrel A. As will be explained in detail, the release of liquid which locks the inner and outer mandrels against movement relative to each other, together with the application of pressure to the upper end of piston 23 functions to effect a release of the packer assembly from its set position. During lowering and initial setting of the packer, the inner and outer mandrels remain in substantially the position shown in FIGURE 1 with the liquid within the cylinder 19 locking the mandrels against movement with respect to each other.

A lower packing element 32 for sealing with the wall of the well pipe 1% or the wall of the well bore and a lower pipe or well bore anchoring unit 33 are supported on the inner mandrel A, while a similar upper packing element 32a for sealing with the wall of the well pipe 10 or the wall of the well bore and upper pipe or well bore anchoring unit 33a are supported upon the outer mandrel B. A piston and cylinder assembly generally indicated by the letter C is disposed between the upper and lower anchoring units, and when actuated, is adapted to move said units as Well as their associated packing elements into a set position. With this arrangement, the packing elements and anchoring units are moved into a set position by the cylinder and piston assembly C. Release of the anchoring units and packing elements is effected by release of the liquid from the upper cylinder 19 and the application of pressure to the upper end of the release piston 23.

The lower packing element 32 is supported upon an annular base or abutment 34, which is suitably secured on the lower portion of the inner mandrel A, said base or abutment being disposed immediately above the coupling 16 which is secured to the lower section 15 of the inner mandrel. Resting upon the upper end of the annular packing element 32 is an annular expander 35, which encircles the inner mandrel A. An inwardly directed flange 3512 on the expander is adapted to engage an external downwardly facing shoulder 35c which is formed on the external portion of the lower tubular section 15 of the inner mandrel. The expander 35 is formed with a plurality of inclined expander surfaces 35d which co-act with the inner inclined surfaces of slip members 37 through the usual dovetail connection (FIGURE 6) to control actuation thereof. The slip members 37 and the expander 35 comprise the usual type or" well-known anchoring unit.

Each slip member 37 is suspended by means of a T- shaped hanger 38 from the lower end of a tubular piston 39, the latter forming part of the piston and cylinder assembly C. The piston 39 surrounds the outer surface of the section 15 of the inner mandrel A and is sealed therewith by a suitable sealing ring 49. Upward movement of the tubular piston 39 on section 15 is limited by the engagement of an internal shoulder 41 on said piston with an external projection 4-2, which may be in the form of a snap ring, provided on the upper exterior surface of section 15 (FIGURE 1).

Co-acting with the tubular piston 39 is a cylinder 43, which encircles the piston in the manner shown in FIG- URE 1. The upper end of the cylinder is formed with an inwardly directed head 44 which is slideable on the lower sleeve portion 18 of the outer mandrel B and is suitably sealed therewith by a sealing ring 44a- Downward movement of the cylinder, with respect to the outer mandrel B is limited by the engagement of the under side of the cylinder head 44 with an external projection 45, which may be in the form of a snap ring, provided on the lower external surface of said outer mandrel.

The movement of the cylinder 43 with respect to the piston 39 is guided and limited by a plurality of inwardly directed guide pins 4d which are secured to the lower portion of the cylinder and which engage within vertical grooves 47 provided in the exterior of the piston 39 (FIG- URE 7). The cylinder is normally retained in a lowered position relative to the piston as shownin FIGURE 1, by means of a plurality of shear pins 48 which function as a releasable retaining means. For introducing pressure into the area between the upper end of the tubular piston and the cylinder head 44 in order to fracture the shear pins 48 and thereafter efiect relative movement of the parts, a pressure inlet port 49 is formed in the Wall of the lower portion of the intermediate section 14 of the inner mandrel A.

port 49 and therefore to the piston and cylinder assembly C, a stop collar 50 is mounted by means of a shear pin 51 in the bore of the lower coupling 16 which is at a point below the lower end of the inner mandrel A. A ball or closure 52 is adapted to be dropped downwardly through the mandrel A and seats on the stop collar 59 to close the lower end of the bore of the inner mandrel, whereby pressure fluid from the tubing T can be applied through the inlet port 49 to act upon the piston and cylinder assembly C to actuate the same.

The upper anchoring unit 33a comprises gripping slips 37a which are connected by means of T-shaped connections 38a with the upper end of the cylinder head 44. Co-acting With the upper gripping slips 37a is an upper slip expander 35a, which encircles the lower sleeve portion 18 of the outer mandrel B and which is formed with inclined expander surfaces 352 slideably engaged through the usual dovetail connection by the slips. Downward movement of the upper expander 35a is limited by the engagement of an internal shoulder 54 within the expander with an annular projection which may be in the form of a snap ring 53; said snap ring is mounted on the exterior of the sleeve portion 13 of the outer mandrel B.

Above the upper slip expander 35a is the upper packing element 32a and the lower portion of said packing element rests upon said expander. The upper end of the packing element 32a is confined by a shoulder or abutrnent 55, which is formed on the outer mandrel B between the upper cylinder portion 19 and the lower sleeve portion 18 of said mandrel.

From the foregoing it will be seen that the lower packing element 32 and its anchoring unit are carried by the inner mandrel A. The upper anchoring unit and the upper packing element are confined on the outer mandrel B and are engaged by the abutment or shoulder 55 thereof. The actuating piston and cylinder assembly C is disposed between the upper packing element and anchoring unit and the lower packing element and anchoring unit. As will be described, the packing elements and anchoring units are moved into set position by the piston and cylinder assembly C and are moved to a released position by the release cylinder 19 and the release piston 23.

In the operation and use of the packer assembly P, said assembly is connected in the tubing string in the manner generally illustrated in FIGURE 8, and is lowered into the well casing 19 by means or" said tubing string. During such lowering, the parts are in the position shown in FIGURE 1 with a liquid being contained within the; cylinder 19 which serves to lock the inner mandrel A against any movement with respect to the outer mandrel B. Upon reaching the position at which the packer is to be set, the tubing string is suspended from the usual tubing head 11 and the control head equipment E, including control valve 12 are properly mounted. Thus, the upper end of the casing is closed in and the well is under control. At this time it is possible to carry out any desired circulating operation since the well packer is in an unset position.

When it is desired to set the packer, the ball 52 is dropped downwardly through the tubing string and inner mandrel and comes to rest on the lower stop collar 59. It is noted that the stop collar 56 has a bore of smaller diameter than the valve sleeve 26 in the upper portion of the inner mandrel A whereby the ball 52 may readily pass downwardly through the bore of said valve sleeve. Hydraulic pressure is thereafter applied through the tubing string and is directed through the inlet port 49 into the piston and cylinder assembly C to act against the upper end of the tubular piston 39 and the under side of the cylinder head 44. The applied pressure within the piston and cylinder assembly C shears the shear pins 48 which normally retain the cylinder 43 in a lowered position with respect to the tubular piston 39, after which the piston and cylinder are moved relative to each other to the position shown in FIGURE 2. The downward force applied to the tubular piston 39 is transferred to the gripping slips 37 of the lower anchoring unit 33 to cause said slips to move downwardly along the inclined surfaces of the expander 35 and into contact with the wall of the well casing 10. Further downward pressure causes the application of endwise force to the lower packing element 32 to expand the same into its sealing position. It is pointed out that since the teeth of the slips 37 are formed to lock against an upward movement of the slips, said slips may ride downwardly along the casing wall until the packing element is set into full sealing contact With the casing.

Simultaneously with the setting of the lower slips and the lower packing element, the cylinder 43 is being urged upwardly which moves the slips 37a of the upper anchoring means 33:: into contact with the casing Wall and thereafter transmits an endwise force to the packing element 32a to deform it into its sealing position. Movement of the piston downwardly moves its stop shoulder 41 downwardly away from the external projection 42 on the inner mandrel A; at the same time the upward movement of the cylinder 43 has moved the cylinder head upwardly away from the stop projection 45 which is formed on the outer mandrel B.

After the packing elements and anchoring units are in set position as shown in FIGURE 2, continued application of pressure against the closure ball 52 will shear the pin 51 which holds the stop collar 59 in position and said stop collar and ball may fall downwardly through the tubing and into the lower portion of the well. The packer assembly is thus in fully set position with the lower slips 37 or" the lowering anchoring unit 33 locking the packer against upward movement in the casing and the upper slips 37a of the upper anchoring unit locking the assembly against downward movement in said casing. The packing elements 32 and 32a, having been deformed into sealing engagement with the wall of the well casing, efficiently seal oil the annular space between the Well tubing and said casing.

When it is desired to remove the packer assembly, release of the anchoring units and unsetting of the packer elements is effected by dropping the second ball or closure 29 downwardly through the tubing and thereafter applying pressure through the tubing string. The ball is of a diameter to seat upon the upper end of the valve sleeve 26 and subsequent application of hydraulic pres sure shears the pins 27 which normally hold the valve sleeve in a position closing the escape port 25; thereafter, the sleeve 26 may move to the position of FIG- URE 3 in engagement with the stop shoulder 39. In such position the port 28 in the wall of the sleeve 26 registers with the escape port 25 and the trapped liquid within cylinder 19 may escape.

Continued application of pressure through the tubing string T directs pressure through the port 31 in the upper portion of the irmer mandrel and into the area between the release piston 23 and the head member 2%, whereby the inner mandrel is urged downwardly and the outer mandrel is urged upwardly. As the inner mandrel moves downwardly with respect to the outer mandrel, the base or support 34% engaging the lower end of the lower packing element 32 is lowered to release the pressure or endwise force which holds the lower packing element in its sealing position. Continued downward movement engages the external shoulder 350 on the inner mandrel with the flange 3513 on the expander of the lower anchoring unit thereby driving the expander downwardly relative to the lower gripping slips 37 to release the same.

Simultaneously the outer mandrel B is moving upwardly and such action relieves the endwise force which was applied to the upper packing element 32a because the abutment 55 on said outer mandrel moves upwardly away from the packing element. By the time that the endwise force has been relieved from the upper packing element 32a, the snap ring 53 on the outer mandrel B has moved into engagement with the shoulder 54 which is formed in the upper expander 35a of the upper anchoring unit 33a. Thereafter, continued upward movement of the outer mandrel pulls the upper expander 35a from between the upper gripping slips 37a to thereby release said upper slips from gripping position. Relative movement of the inner and outer mandrel continues until the parts reach the position shown in FIGURE 4 in which position the guide pins 46 on the piston 43 have reached the upper extremities of the guide grooves 47 in the exterior of the piston. At this time the packing elements and the anchoring units are fully released and the entire assembly may be removed from the well by raising the tubing string T.

From the foregoing it will be evident that a packer assembly is provided which may be efficiently set and moved into sealing and anchoring position by the application of pressure through the well tubing string. Also, when it is desired to release the anchoring units and to return the packing elements to a normal non-sealing position, this may also be accomplished by applying pressure through the tubing string. No motion, either longitudinal or rotational, of the tubing string is necessary so that the setting and releasing of the packer assembly may be carried out without disturbing the tubing string or without disturbing the control head equipment E at the surface of the well. The use of a release cylinder and piston makes it possible to trap an incompressible liquid within the release cylinder to lock the inner and outer mandrel against movement until it is desired to release t e assembly. This provides a simple and efficient means for quickly and easily releasing the anchoring units and moving the packing elements to their normal non-sealing position.

Since the assembly includes both upper and lower pipe or well bore anchoring units, it comprises a permanent type packer which is held against movement in either direction. Any pressure from below the packer assembly when the same is in its set position will merely act against the lower packing element 32 and will be applied to the lower expander to urge the lower anchoring slips 37 into tighter anchoring engagement. Similarly, if the pressure above the packer is greater, this pressure acts downwardly upon the upper packing element 32a and its force is transmitted to the upper expander 35a to urge the upper gripping slips 37a into tighter sealing position. Although employing two anchoring units which lock the assembly against either upward or downward movements, it is possible through the release cylinder and piston arrangement to readily accomplish retraction of the packing elements and anchoring units. As above noted, the results are accomplished by applying hydraulic pressure through the tubing whereby movement of the tubing, disturbing of the control head equipment is not required to actuate the packer assembly.

The foregoing disclsoure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing rom the spirit of the invention.

What we claim is:

LA well packer assembly for connection in a well tubing string within a well bore including, a tubular support consisting of an inner tubular mandrel and an outer tubular mandrel, means connecting the mandrels for limited longitudinal movement relative to each other, an external abutment on each mandrel, means locking the mandrels in a predetermined position relative to each other with the abutments spaced from each other, an upper packing element and anchoring unit for supporting the assembly against downward movement in the Well bore mounted on one of the mandrels and located adjacent the upper abutment, a lower packing element and anchoring unit for supporting the assembly against upward move ment in the well bore and located adjacent the lower abutment, hydraulically-actuated means on the support bethe elements and units into set position confined by the abutments, and means co-acting with said locking means and said mandrels for releasing the locking means to permit movement of the mandrels relative to each other to thereby move the abutments away from said packing elements and anchoring units to move the same to an unset position.

2. A well packer assembly for connection in a well tubing string Within a well bore including,

a tubular support connected in said tubing string,

said support consisting of telescoping sections which are movable longitudinally with respect to each other,

an upper external abutment on one section,

a lower external abutment on the other section,

means for locking the sections against relative movement to lock the abutments in spaced relationship,

an upper anchoring unit for anchoring the assembly in the Well bore and an upper packing element for sealing with the well bore mounted on one section of the support adjacent the upper abutment,

a lower anchoring unit for anchorin the assembly in the Well bore and a lower packing element for sealing with the well bore mounted on the other section of the support adjacent the lower abutment,

a first hydraulically-actuated means carried by the support and located between said upper anchoring unit and packing element and said lower anchoring unit and packing element for applying endwise force to the anchoring units and packing elements which are confined by the abutments, whereby upon operation of said hydraulically-actuated means said elements are deformed into sealing position and said anchoring units are anchored,

and a second hydraulically-actuated means forming part of said support and co-acting with the locking means and the support sections for releasing the locking means and for moving the sections of the support relative to each other in a direction which moves the abutments away from each other, whereby the force maintaining the packing elements in sealing position and the anchoring units in anchored position is relieved.

3. A well packer assembly as set forth in claim 2,

:herein the means for locking the sections of the support against relative movement comprises a cylinder on one section and a piston on the other,

together with means for trapping a liquid between one end of the cylinder and the piston to prevent movement of the piston and its section with respect to the cylinder and its section.

41A well packer assembly as set forth in claim 2, wherein the means for locking the sections of the support against relative movement comprises a cylinder on one section and a piston on the other,

together with means for trapping a liquid between one end of the cylinder and the piston to prevent movement of the piston and its section With respect to the cylinder and its section,

said second hydraulically-actuated means including a valve which normally closes an escape port in the cylinder,

movement of the valve to open position permitting escape of the trapped liquid from the cylinder to allow movement of the piston within said cylinder with resulting relative movement between the sections.

5. A well packer assembly as set forth in claim 2, with means communicating the tubing string with the first hydraulicaly-actuated means, whereby pressure fluid for actuating the said first hydraulicaly-actuated means may be conducted thereto through said tubing string.

6. A well packer assembly as set forth in claim 2, wlth 9 means communicating the tubing string with the first hydraulically-actuated means, wh reby pressure fluid for actuating said first hydraulically-actuated means may be conducted thereto through said tubing string,

and means communi ating the tubing string with said second hydraulically-actuated means,

whereby pressure fluid for actuating said second hydraulically-actuated means may be conducted thereto through the tubing string.

7. A well packer assembly for connection in a well tubing string including,

a tubular support consisting of an inner tubular mandrel and an outer tubular mandrel,

means connecting the mandrels for limited longitudinal movement relative to each other,

means normally locking the mandrels against relative movement,

a lower packing element for sealing with the wall of the well and a lower anchoring unit for anchoring the assembly within the well mounted on one of the mandreis,

an abutment on the inner mandrel engageable with said lower packing element limiting the movement of said element in one direction on the mandrel,

an upper packing element for sealing with the wall of the well and an upper anchorin unit for anchoring the assembly within the well mounted on the other or" said mandrels,

an abutment on the outer mandrel engageable with said upper P; king element for limiting the movement of said eiemcnt in one direction on the mandrel,

hydraulicailyctuated means carried by the mandrels and disposed between the upper packing element and upper anchoring unit on the one hand and the lower packing element and lower anchoring unit on the other hand,

co-acting means on said hydraulically-actuated means and said packing elements and anchoring units operable to m ve said packing elements toward the abutments engaging said elements to thereby set said packing elements and anchoring units when said means is actuated,

it) and hydraulically-actuated means co-acting with the locking means and the mandrels for releasing said locking means to efiect relative movement of the mandrels with respect to each other in a direction to release and unset said packing elements and anchoring units.

8. A well packer assembly as set forth in claim 7, wherein the means for normally locking the mandrels against relative movement with respect to each other comprises a cylinder mounted on one mandrel and a piston mounted on the other mandrel,

together with means for trapping fluid between one end of the cylinder and the piston to prevent movement of the piston within the cylinder to lock the mandrels against movement relative to each other. 9. A well packer assembly as set forth in claim 7, wherein the means for normally locking the mandrels against relative movement with respect to each other comprises a cylinder mounted on one mandrel and a piston mounted on the other mandrel,

together with means for trapping fluid between one end of the cylinder and the piston to prevent movement of the piston within the cylinder to lock the mandrels against movement relative to each other,

and also wherein the hydraulically-actuated releasing means comprises a valve which normally closes an escape port in the cylinder,

movement of the valve to open position permitting escape of the trapped fiuid to allow movement of the piston within the cylinder and consequent movement of one mandrel relative to the other.

References ited in the file of this patent UNITED STATES PATENTS 

1. A WELL PACKER ASSEMBLY FOR CONNECTION IN A WELL TUBING STRING WITHIN A WELL BORE INCLUDING, A TUBULAR SUPPORT CONSISTING OF AN INNER TUBULAR MANDREL AND AN OUTER TUBULAR MANDREL, MEANS CONNECTING THE MANDRELS FOR LIMITED LONGITUDINAL MOVEMENT RELATIVE TO EACH OTHER, AN EXTERNAL ABUTMENT ON EACH MANDREL, MEANS LOCKING THE MANDRELS IN A PREDETERMINED POSITION RELATIVE TO EACH OTHER WITH THE ABUTMENTS SPACED FROM EACH OTHER, AN UPPER PACKING ELEMENT AND ANCHORING UNIT FOR SUPPORTING THE ASSEMBLY AGAINST DOWNWARD MOVEMENT IN THE WELL BORE MOUNTED ON ONE OF THE MANDRELS AND LOCATED ADJACENT THE UPPER ABUTMENT, A LOWER PACKING ELEMENT AND ANCHORING UNIT FOR SUPPORTING THE ASSEMBLY AGAINST UPWARD MOVEMENT IN THE WELL BORE AND LOCATED ADJACENT THE LOWER ABUTMENT, HYDRAULICALLY-ACTUATED MEANS ON THE SUPPORT BETWEEN SAID UPPER PACKING ELEMENT AND ANCHORING UNIT AND SAID LOWER PACKING ELEMENT AND ANCHORING UNIT FOR MOVING THE ELEMENTS AND UNITS INTO SET POSITION CONFINED BY THE ABUTMENTS, AND MEANS CO-ACTING WITH SAID LOCKING MEANS AND SAID MANDREL FOR RELEASING THE LOCKING MEANS TO PERMIT MOVEMENT OF THE MANDRELS RELATIVE TO EACH OTHER TO THEREBY MOVE THE ABUTMENTS AWAY FROM SAID PACKING ELEMENTS AND ANCHORING UNITS TO MOVE THE SAME TO AN UNSET POSITION. 